Battery chargers for charging a low voltage battery from a high voltage battery typically use the entire high voltage battery to reduce down and charge the low voltage battery. Commonly, a high voltage battery is formed of a plurality of lower voltage cells in series. The state of charge of the low voltage battery cells may unequally be discharged when charging the low voltage battery. This may result in a reduced life for the 42 volt battery due to the uneven charging.
It would therefore be desirable to provide a system that increases the life of the high voltage battery by allowing even discharging of portions of the high voltage battery when charging the low voltage battery or providing power to a load.